Electronic devices have continuously aimed at miniaturization. Functionality and portability has improved due to miniaturization, applications have diversified, and they are used in various aspects of society. While miniaturization study of the device itself such as atomic transistor, atom memory devices has progressed, a large change in wiring for supplying power to the device has not been seen. With device miniaturization, current density increases due to miniaturization of circuits and the current density are approaching the limits of the existing conductive materials today. Related to the International Technology Roadmap for Semiconductors (ITRS), current density within devices is said to exceed the fracture limits of copper and gold in 2015. However, carbon based materials having a high current capacity have insufficient electric conductivity as wiring material and the development of new materials is a pressing problem.
To deal with such problems, techniques combining a carbon based material and metal are being developed. For example, a carbon nanotube (hereinafter, referred to as CNT) is known as a lightweight and high strength carbon fiber with excellent electrical conductivity and thermal conductivity, and techniques of applying metal plating to this are being examined. For example, electroplating method is a technique used in various applications, and in addition to conventional techniques using metal ions in a material, techniques are being reported for dispersing fibers or particles to a plating film with the purpose of imparting various functions.
For example, a method of forming a plating film in which CNTs are mixed into metal by adding a dispersion agent and CNTs to a plating solution and dispersing the CNTs in the plating solution is described in the Japanese Laid Open Patent Publication No. 2007-9333.
In addition, a composite material containing aluminum halides, CNTs, 1,3-dialkyl imidazolium halides having an alkyl group of 1 to 12 carbon atoms and/or mono-alkyl pyridinium halides as a nanocarbon/aluminum composite material having both high strength and electrical conductivity is described in the Japanese Laid Open Patent Publication No. 2007-70689.